The object of this part of the program is to make available to the general biomedical community the various microscope control and image acquisition/ analysis procedures developed within the section. The plan is based on the quantitative microscopist having available to him as a minimum system a PC/AT (or a fully compatible MS-DOS machine) with a minimum of 512 Kb of memory and a standard 30 megabyte hard disk. All final interfacing with the microscope will be accomplished via commercially available interface cards which have the appropriate analog and digital signal I/O. Image acquisition hardware will also be of the commercial type. We plan to place in the public domain a series of source programs, written in C (for maximum portability in the PC world) which will allow incrementally more varied and complex functions to be performed on images acquired under computer microscopic control. The procedures which the user can employ will depend upon how much additional resources he has available beyond the noted minimum. Functionally speaking, the programs for control, will for example, apply equally well to inverted microscopy (opening up tissue cultures to controlled image acquisition). Liberal provision is being made in the software for control of additional stepping motor functions which could be user defined (e.g. condenser focus, flow of liquids into and out of a chamber, etc). It is planned to include the possibility for interactive image processing, employing a PC compatible high resolution display with gray level capability. This and other options are available as a function of user interest and the level of resources available on the particular PC or PCs in question.